ele2103 linear systems and control - transtutors · ele2103 – linear systems and control 9 4. if...
TRANSCRIPT
ELE2103
Linear systems and controlFaculty of Engineering and Surveying
In t roduc to ry bookSemester 2 2011
Published by
University of Southern QueenslandToowoomba Queensland 4350Australia
http://www.usq.edu.au
© University of Southern Queensland, 2011.2.
Copyrighted materials reproduced herein are used under the provisions of the Copyright Act 1968 as amended, or as a result of application to the copyright owner.
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without prior permission.
Produced by Learning Resources Development and Support using FrameMaker7.1 on a Pentium workstation.
Table of contents
Page
Essential information 1
Introduction 2Course overview 3
Linear Systems and control 3
Concept map 4
Study materials 5
Study schedule 6
Assessment 7
Late assignment policy 7
Assignment 1 8System modeling, time response and stability 8
Assignment 2 10Block diagram, system performance and responses 10
Past examinations 11
ELE2103 – Linear systems and control 1
Essential information
The topics in the following list provide important information that will assist you with your study. You can access a handout containing the information on your StudyDesk through the ‘Essential information (study materials)’ link <http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/essentialhandout.pdf>. You will need your UConnect username and password to access the file. Please make sure you read this information carefully before commencing your study.
• Getting started <http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/getting_started.pdf>
• Course specification <http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/course_specification.pdf>
• Support <http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/support.pdf>
• UConnect<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/u_connect.pdf>
• Assignment submission<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/assignment_submission.pdf>
• Grading levels<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/grading_levels.pdf>
• Course evaluation <http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/course_evaluation.pdf>
• Residential schools<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/residential_school.pdf>
• Library<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/library.pdf>
• Referencing APA<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/apa_referencing_guide.pdf>
• Referencing Harvard AGPS<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/harvard_referencing_guide.pdf>
• Optional purchase of study materials<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/optional_purchase.pdf>
• USQ policies and procedures<http://usqstudydesk.usq.edu.au/file.php/1/sitefiles/DeC/essential_info/policies_procedures.pdf>
2 ELE2103 – Linear systems and control
Introduction
This course is an amalgamation of two smaller courses in the previous BEng course, viz.
Systems Modelling and Analysis and Control Engineering 1.
• Since the first course was very much a preparation for the second (as well as other areas, of course) it is appropriate to combine the two into a single package. The content of the course and the rationale for it are introduced in module 1, so very little needs to be said here.
ELE2103 – Linear systems and control 3
Course overview
Linear Systems and control
Fourier series
Introduction
Linear Modelling
Root Locus Concept
Laplace Transform
Modelling
ODE Description
Transfer Functions
Design via Bode diagram
Design via Root Locus
Response in Freq. Domain
Fourier Transforms
Frequency response;
Bode diagrams
Block diagrams;
PFs; poles; zeros;
1st, 2nd, high order
Performance improvement;
PID; Phase lead; lag.
Stability; Nyquist & Theorem,
GM, ��� Routh Hurwitz
Signals Systems
Convolution – system
Steady state performance;
Error co-efficients
response in time domain
4 ELE2103 – Linear systems and control
Concept map
Linear
Lumped Parameter
Time Invariant Systems
Described By
Ordinary Differential Equations
Test Signals
Impulse
Step
Ramp
Parabolic
Periodic
Signals
Laplace
Transform
Fourier
Analysis
LAPLACE TRANSFORM
TRANSFER FUNCTIONL
Frequency Domain Behaviour
Inverse
Laplace
Transform
Stability and Behaviour of
Poles and Zeros
Transient
Response
DelaysFirst Order
Systems
Second Order
Systems
Compensation
Routh-Hurwitz
Criterion
Root
Locus
Bode
Plots
Nyquist
Plots
Steady
State Errors
Phase & Gain
Margin
Higher Order
Systems
ELE2103 – Linear systems and control 5
Study materials
Introductory book
References:
Study book: Linear Systems and Control
Textbook: Nise, NS 2008, Control system engineering, 5th edn, John Wiley & Sons, New York.
Support material: Matlab student edition (version 6.0/later and Control Toolbox)
1. Kuo, BC & Golnaraghi, F 2010, Automatic control systems, 9th edn, John Wiley & Sons.
2. Katsuhiko, Ogata 2009, Modern control engineering, 5th edn, Prentice Hall, Inc.
3. Dorf, RC & Bishop, RH 2008, Modern control systems, 11th edn, Prentice Hall.
6 ELE2103 – Linear systems and control
Study schedule
Week Module Activity/Reading Assessment
118–22 July
1. Linear Systems Analysis
Study Book: Module 1Textbook: Chapter 1
225–29 July
2. Laplace Transforms and Transfer Function
Study Book: Module 2Textbook: Chapter 2
31–5 August
3. System Concepts Study Book: Module 3Textbook: Chapter 3+5
48–12 August
4. Time Response Study Book: Module 4+8Textbook: Chapter 4+6
Reminder: End of week 4 is the last date to drop S2 courses without academic or financial penalty.
515–19 August
5. The Root Locus Study Book: Module 5Textbook: Chapter 8
622–26 August
6. Fourier Transform Study Book: Module 6
729 Aug–2 Sept
7. Frequency Response
Study Book: Module 7Textbook: Chapter 10
Assignment 1Due: 2 Sep. 2011
85–9 September
8. Stability of Control Systems
Study Book: Module 8
Reminder: End of week 8 is the last date to drop S2 courses without academic penalty.
912–16 September
BREAK
1019–23 September
BREAK
1126–30 September
9. Control System Characteristics
Study Book: Module 9Textbook: Chapter 7
123–7 October
10. Performance Improvement
Study Book: Module 10Textbook: Chapter 9+11
1310–14 October
11. Controller Design Study Book: Module 11Textbook: Chapter 9+11
1417–21 October
11. Controller Design Study Book: Module 11Textbook: Chapter 9+11
Assignment 2Due: 21 Oct. 2011
1524–28 October
Revision
16–1731 Oct–11 Nov
EXAMINATION PERIOD
ELE2103 – Linear systems and control 7
Assessment
Assessment of this course is via two assignments and an examination; please note the dates for these. A study chart is provided in this book and is offered as a guide with which to check your progress – it might be worth looking at it now and again.
The assessment referred to above is for the purposes of academic administration. The real assessment will come from yourself – if you can use this material appropriately to describe signals and systems, to make valid measurements of their behaviour and, perhaps, to invent and implement a first rate control system then the course will have been a success.
Exam details
The final assessment for this course will be a restricted examination for 700 of the total 1 000 marks for the course. The format of this examination is as follows:
Late assignment policy
Please consult the course specification for up to date information regarding late assignments.
Please also note that assignment extensions are unlikely to be given and that late assignments will be penalised at a rate of 5% per day late.
Perusal – 10 minutes
Duration – 2 hours
This examination assesses all study material.
Drawing, writing implements, and a non programmable calculator are allowed into the exam.
Study materials are not allowed in to the exam venue.
Assessment details
Assignment Due Weighting (%)
Assignment 1Assignment 2Examination (restricted)
2 September 201121 October 2011End of semester
201070
8 ELE2103 – Linear systems and control
Assignment 1
System modeling, time response and stability
Physical system modeling, time response and stability
For a motor, load and torque-speed system shown below
1. Find the differential equation relating input ea(t) and output L(t). (Hint:
where ea(t) and ia(t) are the armature voltage and current, Jm and Dm are the equivalent inertia and damping; Tm(t) is the torque developed by the motor; N1/N2 is the ratio of the gear system.)
(50 marks)
2. Determine the system transfer function G(s)= L(s)/Ea(s). (30 marks)
3. Given Ja=5, JL=700, Da=2, DL=800, N1=100, N2=1000, Ka=5, Kb=2 and Ra=1, obtain the time response for a unit impulse input.
(30 marks)
Due date: 2 September 2011Value: 20%Total marks: 200Penalty for late submission: 5% per day
θL(t)
θm(tea(t)
(t)
θ
)()( ;)(
)()(
)()( ; ;1
2
2
2
1
2
2
1
tiKtT
dt
tdKtiRte
t
N
NtD
N
NDDJ
N
NJJ
aam
m
baaa
LmLamLam
θ
ELE2103 – Linear systems and control 9
4. If the above system is considered as a plant, and a feedback control system is formed as below, for gain K=40, obtain the unit step response of the feedback control system.
(40 marks)
5. Draw a root locus and analyze the stability of the feedback system in 4).(50 marks)
ea(t) L(t) r(t)
Plant + K
10 ELE2103 – Linear systems and control
Assignment 2
Block diagram, system performance and responses
1. Simplify the above block diagram and determine the closed-loop transfer function (Hints: Join summing junction 2 and 3, then simplify the block diagram using parallel, cascade and feedback connections)
(15 marks)
2. If given transfer function and H(s)=1, using Routh-
Hurwitz criterion, find the value of K that will yield oscillations for this unity feedback system.
(20 marks)
3. Given K=307.8 in question 2), draw its Bode plots and determine the gain margin and phase margin for the system).
(50 marks)
4. Given K=307.8 in question 2) again, find the steady-state errors for a unit step input and a unit ramp input respectively.
(10 marks)
5. If you are required to improve the steady state error and make it to be zero for a unit step input, should you choose a PI or PD controller?
(5 marks)
Due date: 21 October 2011Value: 10%Total marks: 100Penalty for late submission: 5% per day
G s( ) 100Ks 15+( ) s 27+( ) s 39+( )
-----------------------------------------------------------=
ELE2103 – Linear systems and control 11
Past examinations
12 ELE2103 – Linear systems and control
STUDENT NAME: STUDENT NO.:
UNIVERSITY OF SOUTHERN QUEENSLAND
FACULTY OF ENGINEERING AND SURVEYING
Course No: ELE2103 Course Name: LINEAR SYSTEMS AND CONTROL
Assessment No: 3 Internal
External
This examination carries 70% of the total
assessment for this courseX
X
Examiner: PAUL WEN Moderator: MARK PHYTHIAN
Examination Date: NOVEMBER 2009
Time Allowed: Perusal – Ten (10) minutes
Working – Two (2) hours
Special Instructions:
This is a RESTRICTED examination.
Writing materials and non-programmable calculators are permitted. Students must note the maker and mode
of the calculator used on the front of the answer book (or examination paper where applicable). This may be
subject to checking by the examination supervisor.
Students are permitted to write on the examination paper during perusal time.
Students must complete questions 1 to 3, and question 4 or 5. Questions 4 and 5 are alternatives. One
and only one will be marked.
All examination question papers must be submitted to supervisors at the end of every examination and
returned to USQ.
Any non-USQ copyright material used herein is reproduced under the provisions of Section 200(1)(b) of the
Copyright Amendment Act 1980.
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2009 Page 1
QUESTIONS 1 TO 3 ARE COMPULSORY
QUESTION 1 (100 marks total)
Briefly describe each of the following terms in the context of linear systems and control. Describe
mathematically, if possible. Do not write more than three dot points per term. (10 marks each term)
1. Open-loop system transfer function
2. Poles and zeros
3. Transient response
4. Steady state error
5. Root locus
6. Bode plots
7. PID controller
8. Phase lead compensator
9. Overshoot
10. Settling time
Page 1 of 9
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 2
Page 2 of 9
QUESTION 2 (200 marks total)
For a mass-spring-damper mechanical system shown below,
Part 1 70 Marks
Verify the following differential equations relating input force f(t) and output displacement x1(t) and x2(t) in the
above system (Hint: K, fv and M are spring constant, friction coefficient and mass respectively)
2
1
2
11
11112212
2
2
2
2
212212
22
3
)()()())()((
))()((
)())()((
))()(()()(
dt
txdM
dt
tdxftxKtxtxK
dt
txtxdf
dt
txdMtxtxK
dt
txtxdf
dt
tdxftf
vv
vv
Part 2 50 Marks
Determine the system transfer function G(s)= X1(s)/F(s)
Part 3 80 Marks
For this part, suppose system transfer function)49.12)(4.1(
3.13)(
2sss
ssG
Obtain the system impulse response in time domain.
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 3
Page 3 of 9
QUESTION 3 (200 marks total)
For a position control system shown in the figure below,
Part 1 50 Marks
Determine the open-loop transfer function G(s)H(s) and the closed-loop transfer function T(s).
Part 2 50 Marks
Find the unit step steady state error of the above system.
Part 3 100 Marks
Design K and K2 in the system to yield an overshoot of 16% and a settling time of 0.8 second.
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 4
Page 4 of 9
COMPLETE EITHER QUESTION 4 OR QUESTION 5
QUESTION 4 (200 marks total, alternative of Question 5)
A floppy disk driver is a position control system in which a read/write head is positioned over a magnetic disk.
The system responds to a command from a computer to position itself at a particular track on the disk. A physical
representation of the system and a block diagram are shown in the figure below
where K is a gain which can be adjusted according to the requirements. Assume K is 1 in your Bode plots
drawing.
Part 1 120 Marks
Sketch the Bode plots for the above system using straight-line approximation, for from 0.1 to 1000
rad/s. Show the sketch procedure. (A graph paper is provided at the end)
Part 2 60 Marks
Estimate the phase and gain margins based on your Bode plots.
Part 3 20 Marks
If you are required to improve system transient response such as overshot and settling time, what simple
compensator/controller should you include in the forward path of the system?
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 5
Page 5 of 9
QUESTION 5 (200 marks total, alternative of Question 4)
The open-loop transfer function of a unit feedback control system is given as
1)2(
4)()(
ss
sKsHsG
p
where Kp is a proportional controller which can be adjusted according to the system design specification.
Part 1 120 Marks
Draw the root locus diagram of the system for 0<Kp<+ and show the drawing steps.
Part 2 60 Marks
Determine the range of Kp for a stable system using Routh-Hurwitz criterion.
Part 3 20 Marks
Briefly explain your conclusion obtained in part 2 using your root locus diagram in part 1.
END OF QUESTIONS
THE FOLLOWINGS ARE EXAMINATION INFORMATION SHEETS
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 6
Page 6 of 9
Selected Laplace Transforms
f(t) F(s)
)(t , Impulse 1
u(t), step s
1
tn
1
!n
s
n
e-at
as
1
te-at
2)(
1
as
)(1 btat
abee
))((
1
bsas
e-at
sin t22)( as
e-at
cos t22)( as
as
Selected Laplace Transform Theorems
Theorem Name
0)()]([)( dtetftfLsF
st Definition
)()()]()([ 212211 sFksFktfktfkL Linearity)()]([ asFtfeL
at
Frequency Shift )()]([ sFeTtfL
st
Time Shift
)(1
)]([a
sF
a
atfL Scaling
)0()()(
fssF
dt
tdfL Differentiation
n
k
kknn
n
n
fssFs
dt
tfdL
1
1 )0()()( Differentiation
s
sFdfL
t )()(
0
Integration
)(lim)(0
ssFfs
Final Value )(lim)0( ssFf
sInitial Value
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 7
Page 7 of 9
Selected Formulae
First order system, its step response & specification
aa
T
a
Tetc
assass
asRsGsC
as
asG
sr
at1
;4
;2.2
;1)(
11
)()()()(;)(
Second order system, its step response & specification
)100/(%ln
)100/ln(%;100%;
1;
4
1tan;1cos
1
11
1sin1
1cos1)(
)2()()()(;
2)(
22
1
2
2
12
2
2
2
2
22
2
22
2
2
OS
OSeOSTT
te
ttetc
sss
sRsGsC
ss
sG
n
p
n
s
n
t
nn
t
nn
n
nn
n
n
n
Mason’s rule
k
kkT
sR
sCsG
)(
)()(
Routh-Hurwitz stability criterion
Steady-state error for unit feedback system and specification
)(lim);(lim);(lim
)](1)[(lim)(lim)(lim)(
2
000
00
sGsKssGKsGK
sTssRssEtee
sa
sv
sp
sst
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 8
Page 8 of 9
Root locus
2,1,0;##
)12(;
##
180)12()()(&1)()( 0
k
zerospoles
k
zerospoles
zerospoles
ksHsKGsHsKG
aa
Controllers
C
C
CCPD
C
PI
PID
ps
zsKsGzsKsG
s
zsKsG
s
bassK
s
sKKsKsK
s
KKsG
)();()(;)(
)(22
3213
21
Frequency response, Bode plots and Nyquist plot
2
2
222222
2
22
2
0
22
2
0
22
2
2222
022
2
n
022
2
2222
0
0
0
0
21;12
1
4)(|)(|
2)(
40log20logMor18011
)(
;01
20log20logMor011
)(
12
11
2
1)(
40log20logMor180)(
;020log20logMor0)(
122)(
20log20logMor901
)(
;020log20logMor011
)(
1
111)(
20log20logMor90)(
;020log20logMor0)(
1)(
npp
nn
n
nn
n
nnn
nn
nnn
nn
nn
nnn
M
jGM
ss
sGFor
whilejG
whilejG
ssss
sGFor
whilejG
whilejG
sssssGFor
whilej
jG
whilea
aa
jG
a
saas
sGFor
whilejjG
whileaaajG
a
saassGFor
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER, 2009 Page 9
Page 9 of 9
You can rescale the axes to fit your plots
10-1
100
101
102
103
104
-200
-150
-100
-50
0
50
10-1
100
101
102
103
104
-200
-150
-100
-50
0
50
Any non-USQ copyright material used herein is reproduced under the provisions of Section 200(1)(b) of the
Copyright Amendment Act 1980.
STUDENT NAME: STUDENT NO.:
UNIVERSITY OF SOUTHERN QUEENSLAND
FACULTY OF ENGINEERING AND SURVEYING
Course No: ELE2103 Course Name: LINEAR SYSTEMS AND CONTROL
Assessment No: 3 Internal
External
This examination carries 70% of the total
assessment for this course
Examiner: PAUL WEN Moderator: MARK PHYTHIAN
Examination Date: NOVEMBER 2010
Time Allowed: Perusal – Ten (10) minutes
Working – Two (2) hours
Special Instructions:
This is a RESTRICTED examination.
Writing materials and non-programmable calculators are permitted. Students must note the maker and mode
of the calculator used on the front of the answer book (or examination paper where applicable). This may be
subject to checking by the examination supervisor.
Students are permitted to write on the examination paper during perusal time.
Students must complete questions 1 to 3, and question 4 or 5. Questions 4 and 5 are alternatives. One
and only one will be marked.
All examination question papers must be submitted to supervisors at the end of every examination and
returned to USQ.
X
X
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 1
Page 1 of 9
QUESTIONS 1 TO 3 ARE COMPULSORY
QUESTION 1 (100 marks total)
Briefly describe each of the following terms in the context of linear systems and control. Describe
mathematically, if possible. Do not write more than three dot points per term. (10 marks each term)
1. System transfer function
2. Closed-loop system
3. Steady state response
4. Damping factor
5. Frequency response
6. Magnitude plot
7. Peak time
8. Settling time
9. Phase lag compensator
10. PID controller
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 2
Page 2 of 9
QUESTION 2 (200 marks total)
Consider a leaky tank system shown below. The inflow is u(t). The outflow is v(t) = ch(t), where c is a
constant coefficient. The volume is given by ah(t), where a is the cross sectional area of the tank. The
net volume gain is given by (inflow – outflow).
Part 1 60 Marks
Write a differential equation modelling the relationship between u(t) and v(t). Then find out its transfer
function )(
)(
sU
sV.
Part 2 40 Marks
The outflow v(t) of the above tank is the inflow to another tank. The second tank has a cross sectional
area of a2, a coefficient c2, and an outflow y(t). For this double-tank system, find out its transfer function
between input U(s) and output Y(s).
Part 3 100 Marks
Given a=c=a2=1 and c2=2, derive the unit step response of the double-tank system.
(Assume )2)(1(
2
)(
)(
sssU
sY if part 2 failed)
Inflow u(t)
h(t)
outflow v(t)=ch(t)
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 3
Page 3 of 9
QUESTION 3 (200 marks total)
For the system shown in the figure below,
Part 1 60 Marks
Determine the open-loop transfer function G(s) and the closed-loop transfer function T(s). (Hints: simplify the
block diagram by shifting the 2nd pick off point to the 3rd)
For the following parts, assume the open-loop transfer function )(
1)()()(ass
KsGsHsG
,
Part 2 40 Marks
Determine the type of the closed-loop system and the steady state error for a unit step input.
Part 3 100 Marks
Determine the value of K and a, so that the percent overshoot %OS of the closed-loop system for a unit step input
is limited to 16.303% and the settling time Ts is 1.6 seconds.
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 4
Page 4 of 9
COMPLETE EITHER QUESTION 4 OR QUESTION 5
QUESTION 4 (200 marks total, alternative of Question 5)
The open-loop transfer function of a control system is )6415(
)(2
sss
KsG
Part 1 120 Marks
For K=128 sketch the Bode plots for the above system using straight-line approximation.
Part 2 40 Marks
Estimate the phase margin and gain margin based on the Bode plots.
Part 3 40 Marks
Is the closed-loop system stable? Explain your conclusion.
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 5
Page 5 of 9
QUESTION 5 (200 marks total, alternative of Question 4)
The open-loop transfer function of a unit feedback control system is given as
)3)(2)(1()(
sss
KsG
p
where Kp is a proportional controller which can be adjusted according to the requirements.
Part 1 100 Marks
Sketch the root locus diagram of the system and show the drawing steps.
Part 2 40 Marks
Based on the root locus obtained in part 1, discuss the system stability when Kp is adjusted from 0 to .
Part 3 60 Marks
Determine the range of Kp for a stable system using Routh-Hurwitz criterion. Does the result agree with your
discussion in part 2?
END OF QUESTIONS
THE FOLLOWINGS ARE EXAMINATION INFORMATION SHEETS
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 6
Page 6 of 9
Selected Laplace Transforms
f(t) F(s) )(t , Impulse 1
u(t), step s
1
tn 1
!ns
n
e-at
as
1
te-at
2)(
1
as
)(1 btat
abee
))((
1
bsas
e-atsint 22)(
as
e-atcost 22)(
as
as
Selected Laplace Transform Theorems
Theorem Name
0
)()]([)( dtetftfLsF st Definition
)()()]()([ 212211 sFksFktfktfkL Linearity )()]([ asFtfeL at Frequency Shift )()]([ sFeTtfL st Time Shift
)(1
)]([a
sF
aatfL Scaling
)0()()(
fssF
dt
tdfL Differentiation
n
k
kknn
n
n
fssFsdt
tfdL
1
1 )0()()( Differentiation
s
sFdfL
t )()(
0
Integration
)(lim)(0
ssFfs
Final Value )(lim)0( ssFf
s Initial Value
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 7
Page 7 of 9
Selected Formulae
First order system, its step response & specification
aaT
aTetc
assass
asRsGsC
as
asG
sr
at 1 ;
4 ;
2.2 ;1)(
11
)()()()( ;)(
Second order system, its step response & specification
)100/(%ln
)100/ln(% ;100% ;
1 ;
4
1tan ;1cos
1
11
1sin1
1cos1)(
)2()()()( ;
2)(
22
1
2
2
12
2
2
2
2
22
2
22
2
2
OS
OSeOSTT
te
ttetc
ssssRsGsC
sssG
n
p
n
s
n
t
nn
t
nn
n
nn
n
n
n
Mason’s rule
k
kkT
sR
sCsG
)(
)()(
Routh-Hurwitz stability criterion
Steady-state error for unit feedback system and specification
)(lim );(lim );(lim
)](1)[(lim)(lim)(lim)(
2
000
00
sGsKssGKsGK
sTssRssEtee
sa
sv
sp
sst
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 8
Page 8 of 9
Root locus
2,1,0 ;
##
)12( ;
##
180)12()()( & 1)()( 0
kzerospoles
k
zerospoles
zerospoles
ksHsKGsHsKG
aa
Controllers
C
CCCPD
CPI
PID
ps
zsKsGzsKsG
s
zsKsG
s
bassK
s
sKKsKsK
s
KKsG
)( );()( ;)(
)(22
3213
21
Frequency response, Bode plots and Nyquist plot
2
2
222222
2
22
2
0
22
2
0
22
2
2222
022
2
n
022
2
2222
0
0
0
0
21 ;12
1
4)(|)(|
2)(
40log20logMor 18011
)(
;0 1
20log20logMor 011
)(
12
11
2
1)(
40log20logMor 180)(
;0 20log20logMor 0)(
122)(
20log20logMor 901
)(
;0 20log20logMor 011
)(
1
111)(
20log20logMor 90)(
;0 20log20logMor 0)(
1)(
npp
nn
n
nn
n
nnn
nn
nnn
nn
nn
nnn
M
jGM
sssGFor
whilejG
whilejG
sssssGFor
whilejG
whilejG
sssssGFor
whilej
jG
whileaaa
jG
a
saassGFor
whilejjG
whileaaajG
a
saassGFor
ELE2103 - LINEAR SYSTEMS AND CONTROL NOVEMBER 2010 Page 9
Page 9 of 9
You can rescale the axes to fit your plots
10-1
100
101
102
103
104
-200
-150
-100
-50
0
50
10-1
100
101
102
103
104
-200
-150
-100
-50
0
50